We had a great time staying at Grant's place for a couple of nights. The flat has an interesting homely decor and was very clean with good facilities and impressive views of the city. Make sure you read Grant's handbook which gives very clear instructions about the building (such as how to get the keys, which without instructions could be quite confusing!).
Grant was very helpful and communicative with all our queries throughout.
Location was great - about 5min walk to Nana station and close to loads of restaurants, shops, etc. There are actually a few restaurants in the building itself - we ate at the poolside restaurants a couple of times which is convenient and decent food!
The only thing I'd flag is that the bed in the second bedroom is actually a big single rather than a double, which you can't really tell from the pictures. This made it a little unbalanced, but as it was only two of us staying it wasn't too much of a problem, but it could be for 2 couples!
It would also be helpful if more than one set of keys could be given out.
However our overall experience was very positive!
Boris